3 Phase Class D amp for DIY BLDC motor Drive

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#641
Pyramid,

I'm trying to help a friend out who built your sinewave generator / 3 phase amplifier to use with a BLWS motor and is now having trouble with it. The issue seems to be the 240 degree output of the amplifier. Measured with a scope to ground, the top half of the signal is clipped. DC bias is also high, over 12 VDC, which I believe is the real fault. All of the polarized caps appear to be in the proper orientation, and the combo had been working for at least a year before failing. Diving into the schematic I found that the board does not appear to agree with the schematics btw. L2 and C14 seem to be swapped with L4 and C16. Probably not relevant to the failure, but was curious if there was a revision to the schematic or board layout.

Any help you can provide would be appreciated.
 
#643
The assembly started working again, which is frustrating from a troubleshooting standpoint. I checked voltages at the caps and everything seemed normal. Since we had one I went ahead and swapped out U2. So far its running normally. It's driving a Michell Orbe, which has a really heavy platter. Is there any issue with initial load overheating the amp? That's all I could think of. BTW, this assembly had been working for at least a year before failing.
 
#646
I've been using the SDP pulley with BLWS motor. Works great, but I'm curious if anyone has had any more luck sourcing or manufacturing a multi-groove pulley like the one Pyramid posted (attached). I'm interested in trying a two pulley setup with a VPI platter.

Anybody have luck with this, or interested in making a one or two pulleys for a fee?
 

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#652
This is a cross-post from the SG4 thread for those who might be subscribed to one thread and not the other:

Does anyone in the US have any spare SG4 and MA-3D PCBs they are willing to part with?
Or should I just order at OSHpark?

Thanks!

Regards,
John
 
#653
Hi all, I'm currently building a turntable and it seems like the SG4/MA-3D combo would be suitable. I'm not yet moderator approved (so unable to PM), but @ralphfcooke if you see this, I would love to purchase the sg4 chip and any other parts you might offer. If you could PM me first that would be greatly appreciated, I'm just in London so a UK supply would be great. Apologies for the slightly redundant message!
Thanks,
Herbie
 
#656
I built this project about two years ago (sinewave generator / 3 phase amplifier/BLWS series). It was working great for the first year, but I've had times when the the motor seems to not have sufficient torque. This is only intermittent and tends to happen when it has been powered on for a while(doesn't matter if it's spinning or paused). Do you have any specific thoughts on what this could be? My initial thought was overheating, but nothing seemed significantly hot?
 
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